In recent years, optical devices, especially LED devices, are expanding their applications as illumination for cellular phones, or as backlights for liquid crystals. These applications are expanding to the general lighting or illumination recently replacing incandescent light bulbs. In general, however, the light-emission efficiency of LED devices in one wafer has a tendency to vary significantly. In addition, these LED devices are still too low in light-emission efficiency to find their use in general lighting/illumination applications, and thus a plurality of LED elements need to be mounted in one LED device.
Among the packaging techniques for these LED devices are one in which LED elements are mounted on an organic substrate of a glass epoxy or the like and after wire bonding, the LED elements are sealed with an epoxy-based transparent resin and then separated into individual pieces using a method called singulation. In another packaging technique, a reflecting plate formed from a white resin such as polyphthalamide (PPA) is molded as a reflecting resin portion on a ceramic substrate, then after LED elements have been mounted on the reflecting plate and wire-bonded, the LED elements are sealed with an epoxy-based transparent resin and separated into individual pieces by singulation. In yet another technique, a reflecting plate is molded with a white resin, such as PPA, on a lead frame, then after LED elements have been mounted on the reflecting plate and wire-bonded, the LED elements are sealed with a transparent resin and separated into individual pieces by singulation.